Tunekicker I am not singling you out here.. I said, "after work, I would come back and make a last response to the thread. No offense taken. I don't mind being singled out if I'm wrong.
My post was a bit unclear. Assuming you already have an audio track, already have a bus for delay, and already have a send from the audio track to the delay bus, inserting a side-chain capable compressor or ducking gate and then sending another send from the audio track to the side-chain input should work as desired.
Side-chaining requires two things- the audio signal that is meant to be affected and heard, and the audio signal that is meant to trigger the affect. You are correct- without an audio send to the bus itself you would hear no sound (unless the listen function is enabled on the side-chained device, but there would be no point to doing this here.)
Sometimes I use the side-chained gate after reverb or delay trick myself, for the opposite affect- I only want the delay to happen when the vocal is in the midst of a phrase, and don't want delay tails hanging out after the vocal is done.
Separating the audio signal and trigger signal out, there are essentially 3 useful options:
1. Gate before delay, non side-chained. The gate responds to the dry signal and affects the dry signal, which is then sent to the delay. No trigger signal is present. Delay tails would decay naturally.
2. Gate after delay, non side-chained. The gate responds to the wet signal and affects the wet signal. No trigger signal is present. Delay tails would be cut of when their level drops below the gate's threshold.
3. Gate after delay, side-chain turned on, with audio routed directly to the bus and to the gate's sidechain input. The gate responds to the dry signal (trigger) but affects the wet signal (audio.) Delay tails would be cut off as soon as the vocal stops (with the attack time as a buffer.)
This can be fun to have an affected vocal track that doesn't have delay tails that hang out when the vocalist stops singing.
Peace,
Tunes